Rock-paper-scissors seems to be a game of equal chances. Play the game randomly and you should win a third of the time. However, being humans with odd psychology, that’s not how we play at all. In fact, knowing how we really play can help you win RPS all the time. With statistics and game theory no less.

Dr. Hannah Fry explains in a recent Numberphile video how we can use human psychology and a bit of game theory to our advantage:

Based on the statistical trends that came out of those 360 students playing 300 rounds of RPS, a winning hand comes down to taking advantage of two psychological quirks. First, because players who win a round of RPS tend to repeat their winning choice, if you lose, you should change to the selection that didn’t get beaten. For example, if a player beats you with rock, you should chose paper in the next round.

The next tip is where game theory comes in. If you’ve just won, the loser might assume that you are going to repeat your choice (as the statistics support). So they will switch to the selection that wasn’t beaten. In response to that bit of knowledge, winners should play what the loser just played when they lost to have the best chance of beating them. It’s complicated but effective, and Dr. Fry explains it beautifully.

Or you could just be a robot that moves so quickly it can first sense your choice and then choose the winning selection before a human brain can process it.

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IMAGES: Numberphile